// -------------------------------------------------
// BlinKit - BlinKit Library
// -------------------------------------------------
//   File Name: CustomElementObserver.h
// Description: CustomElementObserver Class
//      Author: Ziming Li
//     Created: 2021-08-26
// -------------------------------------------------
// Copyright (C) 2021 MingYang Software Technology.
// -------------------------------------------------

/*
 * Copyright (C) 2013 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer
 *    in the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name of Google Inc. nor the names of its contributors
 *    may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef CustomElementObserver_h
#define CustomElementObserver_h

#include "platform/heap/Handle.h"
#include "wtf/HashMap.h"

namespace blink {

class Element;

class CustomElementObserver {
public:
    virtual ~CustomElementObserver() { }

    // API for CustomElement to kick off notifications
    static void notifyElementWasDestroyed(Element*);

    DEFINE_INLINE_VIRTUAL_TRACE() { }

protected:
    CustomElementObserver() { }

    void observe(Element*);
    void unobserve(Element*);

    virtual void elementWasDestroyed(Element* element) { unobserve(element); }
};

} // namespace blink

#endif // CustomElementObserver_h
